reporter: just as mandela brought his country together, his memorial began with a coming together of religions, during an interfaith prayer. >> he, too, transcended his personal pain and years of suffering, to forgive and to embrace his brothers and sisters, who inflicted so much pain on him. >> to madiba for his selfless efforts, salvaging the nation and leading it to the path of peace, reconciliation and harmony. >> reporter: then, a song to nelson mandela. ♪ nelson mandela >> reporter: 3 of mandela's 18 grandchildren and 12 great-grandchildren, took the stage to honor their grandfather. >> the tree that towers above the rest is broken by the wind. child of the wind. of the land. child that dreams of a future where black and white, rich and poor, men, women and children, must live side by side, dreaming the same dream, realizing at the crucible of time in our land, we salute you. >> so many emotional tribute this is morning. so many world leaders there, including four american presidents. kind of surprising. not a lot of visible security. >> reporter: given how many of the world's most pow